Air hammer



June 10', 1924. H 1,497,635

-' F. H. PARRISH AIR HAMMER Original Filed quly 5, 1921 2 Sheets-Sheet l A fforneya.

Fa rfax Parr/sh.

June 10 1924. 1,497,635 I F. H. PARRISH AIR HAMMER Original Filed July 5 1921 Z Sheets-Sheet 2 jm/emon Fai fax Parr/sh.

A fforneys Patented June 10, 1924.

FAIRFAX HAYES PARRISH, F DALLAS, OREGON.

AIR HAMMER.

Gontinuation of application filed .Tuly 5, 1921, Serial No. 482,636. This application filed September 24,

' 1923. Serial No. 664,593.

To all whom it may concern:

Be it known that I, FAIRFAX H. PARRISH,

a citizen of the United States, residing at Dallas in the county of Polk and State of Oregon, have invented certain new and useful Improvements in Air Hammers; and I do declare the following to be a full, clear,

and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to an air hammer of such size and construction that the device can be operated in the hands of the work man, and'the power by which the air is compressed to operate the striking mechanism is created by means of an electric motor directly connected to the hammer and forming a part thereof and is a continuation of my abandoned application Serial No. 482,636 filed July 5, 1921.

Objects of my invention are; to construct an air hammer which is driven by an electrio motor directly connected thereto and which can be operated at any desired position in the hands of the workman; to proride means for controlling the blow delivered by the hammer; to eliminate the shock delivered by the hammer to the 0perator during the operation of the machine; to provide means for supplying air to the compression cylinder when the blow from the hammer is made; to construct a cylinder which will rotate about the striking piston installed within and to provide a switch for controlling the operation of the motor while the machine is being held in the working position.

I attain these objects by the mechanism e0 illustrated in the accompanying drawings in which:

Figure 1 is a sectional view of the hammer completely assembled withthe driving motor directly connected through the reducing gears.

Figure 2 is a sectional View of the driving gears and shaft in which the armature shaft rotates.

Figure 3 is an elevational view of the driving plate of the cylinder (on the left) and'an end View of the cylinder head (on the right).

Figure 4 is a sectional view of the hammer and housing taken along the line A-A in Fig. 1.

Figure 5 is a sectional View of the piston and cam roller mounted on the cam pin.

Figure 6 is a perspective of the cam which is installed in the compression cylinder about the piston. v

Figure 7 is a sectional view of the valve mounted on the piston head through which the supply of air passes to the compression chamber in the head of the cylinder.

Similar numerals refer to similar parts throughout the several views.

A cylindrical housing 1 encloses the hammer mechanism and also forms a carrier for the several parts as well as for the motor and reduction gears. The motor armature 2 is mounted on the armature shaft 3 which has 'a center line common to the hammer mechanism. The bearing 4 in the partition 5 carries the armature shaft with the pinion 6 mounted on the same within the gear chamber 7. A counter-shaft 8 is carried in the bearings 9 provided in the gear chamber housing, upon which a gear 10 is mounted and alined to mesh with the pinion 6 on the armature shaft. A pinion 11 is mounted on the counter-shaft 8 and alined to mesh with the gear 12 which is fastened to a sleeve shaft 13 loose on shaft 3. In this manner there are two bearings formed in one. The sleeve shaft 13 extends through the housing 1 1 and has a transmission plate 15 fastened to its front end. The arrangement of the parts can be understood by examining the sectional view where the armature shaft is shown in the center.

A thrust roller bearing 16 is mounted about the bearing extension and the sleeve shaft 13 and between the gear housing 14 and the transmission plate 15. This hearing is to take the thrust from the cylinder and reduce the friction between the moving parts.

Three pins 17 are set in the head of a cylinder 18 at equal distances about the face thereof, there being portions of said pins allowed to project from the face to engage the transmission plate 15 by inserting the same through the holes 20 provided at corresponding positions in the plate. The extended end of the shaft 13 and the hub of the transmission plate are received in a well 21 provided for the same in the head of the cylinder.

.The end of the cylinder 18 remote from the head is fitted to a cam cylinder 22 with the cam assembled within the cylinder in the manner shown in Fig. 1. The parts are held together by the screws 23 and an oilset is provided in the cam cylinder to allow the cylinder to be fitted to the same without having an irregular outside surface. The shaft 18 carries one end of the cylinder 18 and ball bearings 24 are provided to carry the remaining end with the end of the cam cylinder acting as a bearing for the cylinder 18 through the balls to the outside housing. The cylinder is subject to rotate in the two bearings mentioned free from the outside housing.

A plunger 25 has'two shouldersthroughout its length and a piston head 26 on said plunger is received in the cylinder 18, and grooves are provided to receive the piston rings 27, making an air tight chamber in the head of the cylinder 18. In front of the piston headproper, the intermediate plungerporti'on 28 is constructed of such sectional size, a'stoan'ake a moving lit in thecam cyl- 'indeI'QQF This portion of the plunger is of suchleng'th as to have a bearing in the cam cylinder at all times. A cam roller 29 is mounted on a pin 30 carried by the plunger to project from the same and engage with the cam provided on the cam cylinder 22.

This can be understood fromtthe sectional View inFigure 1 of the drawings. Another reduction ismade in the piston rod and forms a stem 31 extended to the hammer 32 which is assembled to operate in the forward end of the housing. Guides 33 are formed in the housing 1, in which the pin 3 1: mounted to project from the stem 31. guided. This arrangement to prevent the plunger from rotating when the machine is in operation.

I The cam cylinder 92 18 formed with a cam of thetype shown in Fig.6, where the return isfconstructedto fall parallel with the center line ofthe hammer which is also the direction in which the hammer is operative. A shoulder 35 is provided on the inside of the forward end of the cam cylinder to mn 'c a close fit with the -stem'31 passing therein. Air passages 36 are provided in such position in the walls of the cam cylinder 22, as to allow a closed chamber about the plunger to compress air, when the hammer is in the forward position.

A shock-absorbing spring 37 is coiled about the stem 31 ofthe plunger, and operates against the shoulder within the cam cylinder 22 and the first shoulder on the plunger. This spring is so constructed as to take action at the latter part of the motion of the hammer only. In this manner the shock delivered to the housing of the hammer when the mechanism is in operation. is reduced, and thus the operator will not receive the shock that a common fault in air hammers in use.

A valve 38 is fitted to the head of the piston in a manner to admit air to the cylinder and retain the same in the chamber. The valve closes the passage 39 which provided in the plunger to extend from the valve to the smallest sectional part 'll of the plunger. where an opening is provided to connect the same with the air chamber in the cum cylinder. This will be better. understood after reading the description of the operation, which will follow later in the specification.

The extreme forward end of the housing is fitted with a threaded portion to receive the nose or tool carrier 4-0. Means are provided to prevent the tool 4-1 from slipping from the head of the machine. but the tool is held in such position as to receive a blow from the hammer and deliver the same to the work. The part -1l0 which carries the tool can be turned on the housing to bring the striking head of the tool farther from the hammer head. This being done. the strength of the blow delivered to the tool can be governed and any desired blow can be used to suit the ease in hand. ()t coursc it is understood that a number of dillercnt tools can be fitted to the mechanism and used to advantage about different kinds of work.

The housing of the motor 4-) is built in one piece and provided with the shoulder l3 about a drum-like part 4.1 which is made to fit the enlarged rear end of the hammer housing 1. The motor is therefore sliduble in the housing of the hammer with the gear case. A similar shoulder 4:5 is formed on the hammer housing 1. adjzu'cnt to the shoulder 4C3 when the parts are assembled. The two housings are held together by bolts ll, which hav oiled about them between the nut and. shoulder 1-5. the coil springs '17. This arrangement is provided to eliminate the shock from. the hand and body of the operator.

The handle 4-8 is connected to the head of the motor housing 4-2 in thc manner shown in Fig. 1 and an electric switch it? is installed at some convenient point in the hair dlewhere it can be operated without rcmov ing the hand from the holding position.

The operation of the electric air hanuucr is as follows:

The machine is held. by both hands, one

of which is placed on the handle at tbc bcud Ill loo

l bi

llo

ill

tion is transmitted to the cylinder 18 through the shaft 13 and reducing gears. Since the cam cylinder 22 is connected to the compression cylinder 18, it will rotate in the same direction as said compression cylinder. The plunger 25 is prevented from rotating by the pin 34 through the forward end thereof, which is carried in the guides 33 in the for- Ward end of the hammer housing. From this it will be understood how both the compression and cam cylinders rotate Within the housing and about the plunger. The roller 29 provided on the plunger 25 is engaged with the cam on the rear end of the cam cylinder 22 and this cylinder is rotated in the direction to allow the roller to climb the incline of the cam and disengage at the point where the cam makes a straight return to the point of beginning. In this manner the plunger is forced to thehead of the cylinder and the air in this cylinder is brought into compression thereby. When the roller passes the high point on the cam, the compression between the head of the cylinder and piston head 26 forces the plunger to the forward position and a blow is delivered to the head of the tool. The shock from the blow is taken up through the spring 37 coiled aboutthe piston stem and the springs 4:7 about the bolts 46 assembling the motor and hammer housings.

lVhen the shoulder on the piston passes the passages 36 in the cam cylinder 22 air is compressed in the front end of this cylinder and forced through the passage 39 and by the valve 38 to the chamber at the head of the piston. In this manner air is supplied to the rear compression chamber to maintain the proper amount of air therein.

The blow delivered to the tool is governed by turning the nose 4:0 to the desired point with the hand in which it is held.

I am aware that there are other hammers in use, but there are features of my invention which are new to the art and therefore it is understood that minor changes in the precise embodiment of the parts will not depart from the spirit thereof.

I claim:

1. A pneumatic hammer comprising an elongated housing, a plunger therein adapted to compress air when forced rearwardly, a rotary cam in the housing for successively forcing said plunger rearwardly and releasing it, and a rotary carrying and driving member for said cam surrounding said plunger-and constituting a cylinder therefor in which air compression takes place when said plunger is forced rearwardly.

2. A pneumatic hammer comprising a cylindcr having a head at its rear end, an opening in its front end and an air inlet adjacent said front end, a plunger in said cylinder having a stem at its front end passing through said opening, said plunger. having a piston head at its rear end for coaction with the cylinder head in compressing air when the plunger is forced rearwardly, said plunger also having a shoulder cooperable with the front end of said cylinder to compress air at the completion of each forward stroke, a check-valved compressed air passage from the front portion of the cylinder into the rear portion thereof, and means for successively forcing the plunger rearwardly and releasing it.

3. A structure as specified in claim 2; said shoulder being movable over and controlling said air inlet.

4. A structure as specified in claim 2; said compressed air passage being formed in said plunger.

5. A structure as specified in claim 2; together with means for rotatably mounting said cylinder, and means for holding said plunger against rotation; said means for forcing said plunger rearwardly comprising coact-ing elements on the cylinder and plunger operable by rotation of said cylinder.

6. A pneumatic hammer comprising an elongated housing, a rotary driven cylinder mounted longitudinally in said housing and having a head at its rear end, an opening in its front end and an air inlet adjacent said front end; said cylinder being formed of a relatively long rear section and a comparatively short front section fitting within said rear section, the rear end of said front section having a cam a plunger within said cylinder having an air compressing head at its rear end cooperable with said cylinder head, the front end'of said plunger having a stem passing through the aforesaid opening and non-rotatably connected with said housing, said plunger also having an aircompressing shoulder cooperable with the front end of the cylinder, a check-valved compressed air passage from the front portion of said cylinder into the rear portion thereof, and a shoe on the plunger cooperable with said cam to effect successive rearward movement and release of said plunger when said cylinder is rotated.

7; A pneumatic hammer comprising an elongated housing having an enlarged drumlike rear end, a gear housing slidably receivedin said drum-like rear end, means for cushioning the relative sliding of said housings, a motor connected with the rear side of said gear housing and having a shaft extending into the latter, gearing in said housing driven by said shaft, another shaft driven by said gearing and extending into the first-named housing, and hammer mechanism in said first-named housing operated by said other shaft.

In testimony whereof I have hereunto affixed no signature.

f AIRFAX HAYES PARRISH. 

